They don't need the A-10. They need aircraft that can perform the mission that the A-10 is commonly used for.
Aircraft that perform that mission include AH-64's, F-16's, F-15's, AV-8b's, B1b, drones and the list goes on.
A-10's have become popular because everyone thinks the gun is cool because big must be better. Soldier's on the ground like it because for for several years it was seen as the best way to issue a "fuck you" to the other people shooting at them. Having the ability to make multiple passes to issue that "fuck you" is a bonus. They are paid for. They are cheap to operate. They are cool looking.
that being said
The A-10 itself is not needed.
The A-10 can only thrive in an environment where we have complete air superiority. The gun's effectiveness as a tank killer is overrated. It's great against older tanks. Not so much against modern tanks. When the A-10 was developed, missile tech was still on the shitty side. We tossed that gun on there because it was the right solution at the time to deal with all the expected T-55's and T-62 coming our way in Europe. In modern times, we have very effective stuff that do the job more effectively.
We have lots of tank killers nowadays.
If we have complete air superiority and you need to provide CAS
1. Hornets F-15E\Harriers\AV-8b's are quicker to the target area
2. Apaches\Cobras can get into the meat and potatoes with you
3. One B1b can park itself up at "what's that dot in the sky up there" and provide complete coverage for hours and then switch off with another B1b. (Sniper pod+fancy boom sticks)
So you can have fast jets get to you "NOW" and have them do it in one pass.
You can wait for the A-10's to arrive to be able to make 2 or 3 passes
You can have a Helicopter hang out for awhile but then you are waiting forever. And occasionally you have to rescue the Helicopter.
You can have a B1b get their "now" and then park itself overhead for a couple of hours. Just have to hope some other asshole 300 miles is making the same request.